Turboblade fastening



May 28, 1946. w. HUB ER TURBO BLADE FASTENING Filed July 15, 1943 v INVENTOR. WALTER H0853.

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Patented May 28, 1946 TURBOBLADE FASTENING Walter Huber, Winterthur, Switzerland, assignor to Sulzer Freres, Societe Anonyme, Winterthur, Switzerland Application July 15, 1943, Serial No. 494,776 In Switzerland October 23, 1942 1 Claim.

The invention relates to a turbomachine having blades with. wedge-shaped roots let into grooves of wedge-shaped cross-section. The invention consists in that the cross-section of the groove is wider than the blade root and that the space remaining between the blade and one side wall of the groove is filled by a ring. This ring may, for example, be rammed into the groove. The cross-section of the groove is made so much wider than the blade root that the blades can be inserted at every point of the groove without the use of a lock. Preferably the side surface of the blade root which lies next to the inserted ring is arranged parallel to the blade axis, and the opposite surface of the blade root which is in direct contact with one of the side walls of the groove is arranged obliquely to the blade axis.

The inserted ring may be divided into several bars, for example into at least two layers lying one above the other in the groove. The bars ly-' ing topmost in the groove may be held firm by caulking the blade carrier. The space between blade root and groove surface filled by the in serted ring may have a slightly tapered crosssection.

An example of the subject matter of the invention is represented in simplified form in the drawing.

Fig. 1 shows a part of a longitudinal section through a turbomachine.

Fig. 2 shows the cross-section and Fig. 3 the longitudinal section, along the line IIIIII of Fig. 2, of a single element of the turbomachine according to Fig. 1, both on a larger scale.

In the blade carrier I (Fig. l) of a turbine or axial compressor rows of guide blading 2 are inserted in grooves 3.

The blades 4 (Figs. 2 and 3) of the guide blading as shown in Fig. 1 have their wedge-shaped roots 5 fitted into grooves 6 of wedge-shaped cross-section. The cross-section of the groove is wider than the profile of the blade root, so that between the side surfaces l I of the blades and the side wall I of the groove a space is left which is filled by an inserted ring. The ring is by way of example divided into three bars 8, 9 and I0 lying one above the other in the groove.

First the bar 8 is introduced and rammed in until it fits close to the side surface 1 of groove 6 and to the side surface H of blade root 5. Then the bar 9 is introduced and similarly rammed in.

Finally the bar II] is inserted and is made firm by caulking the edge 12 of the blade carrier l. The blade carrier may at first have a projecting edge I3 so that no depression is caused by the caulking.

The bars themselves may be divided into several sections circumferentially. The insertion of the blades is then facilitated in that, after the introduction of a number of blades arranged in a row for the length of one section, at least one ring section can be inserted and rammed in. In this way one section after another can be inserted until finally the blading is completed.

The fitting of the blades described above can be adopted both for the runners and for the stationary blading of turbines or compressors and is particularly suited for the stationary blades of turbines. The design described in the invention can be employed for radial flow machines as well as for axial turbomachines. A suitable material from which the inserted rings or bars may be constructed is, for example, soft iron. It may be advantageous for the outermost ring against which the edge of the groove is caulked to be made harder than the others.

I claim:

A turbomachine comprising a blade carrier, at least one groove in the carrier for the blades, said groove having one side oblique and the opposite side parallel to the blade axis, the roots of the blades being sufficiently narrower than the groove that the roots may be inserted into the groove, said roots of the blades having one oblique face which cooperates with the oblique side of the groove to wedge the blades to the carrier and the opposite face parallel to the parallel side of the groove, ring means in the groove filling the space defined by the parallel face and side when the oblique face of the root is in engagement with the oblique side of the groove, and caulking for securing the ring means in position, said ring means being divided into at least two rings the outermost of which is harder than the other which is nearer th bottom of the groove, so that the ring near the bottom of the groove may be rammed into the groove and the outermost ring is held in position by caulking the edge of the groove against it.

WALTER HUBER. 

